$1,000 could be a DEAL when it comes to getting Tom Brady's autograph ... so says NFL Hall of Famer Shannon Sharpe, who tells TMZ Sports the G.O.A.T. could charge A LOT more.
TMZ Sports broke the story ... Brady is doing a private autograph session with a sports memorabilia company next month and the prices start at $850 for a photo! Footballs are $1,000.
But the co-host of FS1's "Undisputed" says Brady could charge more than DOUBLE that if he wanted to .